These things add tautness to the ride, and won't be felt as improvements if a stiffer ride isn't what you were after. And stiffer eventually means more squeaks, not fewer.

These things, will however, make the car better at cornering. I don't think swaybars from IPD will help, even if they're available. I believe they've been unable to engineer a significant improvement, as FWD Volvos apparently have a pretty effective rear swaybar. A tower brace will help with turn-in because it helps counteract the incipient 'lightness' typical in FWD steering (IPD's is $250, a Volvo-branded alloy is $150 -- why didn't this come installed as original equipment?). But again, this increases torsional frame rigidity, and some have complained about the development of new squeaks especially in the dashboard.

One thing we both forgot to mention: front swaybar endlinks.